Introduce io.quarkus.code.java-version config

[gastaldi]

This PR introduces a io.quarkus.code.java-version config property that allows setting the default Java version to be used.

It allows us to set the production instance to use JDK 11 by default as requested in https://issues.redhat.com/browse/QUARKUS-2451

[github-actions]

🙈 The PR is closed and the preview is expired.

[ia3andy]

I am not sure this would be a good idea:

• it introduces a public field that we need to maintain
• it's not yet used by the rest clients (IDEs)
• it won't be compatible and possibly conflict if we decide to have different default JDKs depending on the platform

[gastaldi]

• it introduces a public field that we need to maintain

Not sure what you mean here, it's an optional value and a config property just like the others

• it's not yet used by the rest clients (IDEs)

Of course not, this is a new feature :)

• it won't be compatible and possibly conflict if we decide to have different default JDKs depending on the platform

Yes, this is a workaround until quarkusio/quarkus#28497 is implemented

Anyway, if the intention is to wait until the above issue is implemented, I am fine with closing this PR

[ia3andy]

I am closing this as it has been decided that having a "static" java version is not the way forward.

Instead we should have this coming from the registry per stream:

• Available JDKs
• Default JDK